The study of the relationship between structures and functions is at the very heart of biology. This relationship is expressed in living beings by the adaptation of the first to the second and poses a series of absolutely fundamental problems, such as the relationship between causality and finality, analogy and homology, structural improvement and evolutionary level, etc.
For example, the structure of the hand is related to its function, thanks to the fingers and the thumb it is easy to wear and store objects.
The zigzag structure of the intestine is related to its absorption function, as this makes it possible to increase the contact surface between the alimentary bolus and the intestinal wall, and thus to increase the absorption.